System and method of lubricating compressors



Jan. 24, 1933. E.'T. WILLIAMS 1,895,092

SYSTEM AND METHOD OFl LUBRICATING lCOMPl'E-SSORS original Filed July 31, 1926 2 sheets-sheet 1 Jan.`24, 1933.I E, T, w|| 1AM$ 1,895,092

SYSTEM AND METHOD OF LUBRICATING COMPRESSORS Original Filed July 3l. 1926 2 Sheets-Sheet 2 Patented dan. 24, 1933 UNITED STATES PATENT OFFICE SYSTEM AND METHOD OF LUBRICATING CQMPRESSOBS rizinal application le duly 31, 1926, Serial No. 126,172, now Patent No. 1,750,298. minded anti this application led April 2, '1929. Serial No. 352,012. i

This yapplication is a division of my coending application Serial No. 126,172 filed guly 31, 1926 now Patent No. 1,750,293.

This invention relates to compressors and 5 more particularly to a system and method of lubricating compressors in which rotors are mounted eccentric to the cylinders. Y

It has among its purposes to produce a rotary compressor having perfection in its lu- `10 brication system to such an extent as to insure thorough lubrication of all moving parts during the operation of the compressor, the lubricant bein maintained in a continuous state of flow y a difference in pressures which/will cease to be existent upon the stoppage of the operation of the compressor. Another object resides in supplying the correct quantity of lubricant to the cylinder of a compressor under various operating loads and in introducing some of the lubricant into the cylinder at such particular laces as to cause it to form an eiiicient seal etween the high and low pressure sides of the rotor.

Another object resides in effectively 1ncreasing the sealing efiiciency betweenV the rotor and the cylinder.

A still further object is to increase the sealing eiiiciency'between the iat sides or ends of the rotor and the cylinder cover-plates. The question of tolerances in this matter, that is ermissibility in variation of measurements, as given manufacturers of rotary compressors a great deal of trouble, so much so, that compressors of the rotary type may be said to have met with only mediocre success. Expansion and contraction play a part in the matter/vof end clearance. Too small a clearance at low temperature is liable to result in binding at higher temperature. To overcome the difficulties incident to the problem of end clearance, I propose to sub-divide the clearance space by using one or more axially movable disks at each fiat side or end of the rotor. These disks space themselves due to oil pressure. By so doing I can build a compressor with an actual clearance ot, say, one thousandth of an inch at each end while having an effective clearance in operation, of only one-third of a thousandth of an inch.

In a compressor not equipped with these loose disks, having only one oil space between each end of the rotor and the adjacent cylinder cover, if the tolerance allowed is too great the eiciency and amount of ressure obtainable'are low. To get high e ciency, low end clearance is necessary, but the manufacture of parte with suiiiciently small clearances would e too expensive. Furthermore there is the danger of binding which is eliminated in the present invention.

To illustrate this phase of the invention, assume a total clearance of 0.002 inch between the flat sides or ends of the rotors and the' adjacent cf ver-plates and assume that we insert one loose disk at each end. The total clearance will now be divided into four spaces 'of 0.0005 of an inch width each. Thus the employment of only two disks 'ves an effective clearance reduction of fty percent. More disks will give still greater reduction. Other objects and advantages are brought out more fully in the description and claims.

The drawings illustrate a preferred embodiment of my invention and Fig. 1 illustrates a vertical section of a. compressor on line 1-1 ofFig. 2.

Fig. 1A is a detail on line 1A-1A of Fig. 1.

Fig. 2 is an end view of a cylinder and rotor taken on line 11-11 of Fig. 1.

' Fig. 3 is a diagrammatic plan-view illustrating the external paths of Ifiow of the lubricant. v

\ The compressor illustrated is a two-stage compressor of a built up type in which the cylinders 10 and 1'1, and rotors 12 and 13 are iianked by cover-plates 14 carrying bearings 15, 16, and 17 for the rotor-shafts.

The compressor is illustrated as being supported by a frame 18 at one end. Each cylinder has an inlet port 19.(Fig. 2) and an outlet port 20. Communicating with the inlet port 19 of the first stage compression cylinder 10 is an oil passage 21 through which oil is introduced into the low pressure side of that cylinder and into the path of the inlowing refrigerant which picks up the oil and thoroughly disperses it within the cylinder. In addition to lubricating the blades 22, the oil serves to form a seal at the line of contact 23 between the rotor and the cylinder, and,

after having thoroughly lubricated the bore of cyilindei 10, all -of the oil within the cylinder is discharged with the com ressed refrigerant through conduit 23a (ig. 3) to the low ressure sido of the second stage compression cylindeil 11 in which it sei-ves to lubricate that cylinder in the manner just described. v The refrigerant discharged from the high pressure side of the second stage compression cylinder 11 is conducted to an oil separator 23? (which may also include a storage chamber or reservoir). The oil which is separated from the refrigerant is returned under pressure to the compressor through conduit 24 which is connected with the oilerbod 25. The oiler-body 25 discharges into the ow pressure side of the first stage compression cylinder 10 in a manner to be described hereinafter. It is apparent that the oil will continue to follow the cycle just described as long as a differential pressure exists and, consequently` as long as the compressor is operating. Upon a discontinuance of operation, the oil ow will stop and no oil will accumulate in the cylinders. In Fig. 3 I have chosen to exemplify my lubrication system by illustrating this complete cycle of lubricant flow, and reference may be had to my United States Patent No. 1,392,997 for details of construction of an oil separator and associated parts.

The cycle of oil flow just outlined may be considered-as comprising the primary circuit and the course of the lubricant which serves to lubricate the various bearings and effectively seal the sides of the rotors will now bedescribed. Considered asa whole, it will be appreciated that all of the oil supplied to a cylinder will serve to create a sealing relation adjacent all contacting surfaces of the rotor and `thereby maintain uncommunicable the high and low pressure sides of a single cylinder. The circuit desi ed to lubricate the various bearings inclu es a conduit 26 whichl is connected conveniently to oiler-body 25 so as to receive oil'direct from conduit 24 and conduct it to an oil passage 27 drilled in an end cover-plate and piercing bearing 17. Oil passage 2 leads directly to an annular groove 28 on the inner surface of bearing 17. A. plurality of linear grooves along the inner surface of bearing 1 serves to conduct oil to a closed space 29 at the end of the shaft of rotor 13. The rotor shafts have holes 30, 30 along their axes so that space 29 is directly connected with space 31 which is defined by the inner surface of a bellows 32 and ring 33 to which the far end of the bellows is secured. Ring 33 contacts collar 34 which iotates with the shaft. Ring 33 is supported by a collar 35 which is itself held in place by a nut 36 screwed' to the hub 37. The present invention is not concerned with any particular design of shaft sealing device except sides of the rotors and they to the extent of using one which permits of lubrication around the rotor shaft.

The shaft of rotor 12 is connected to the shaft of rotor 13 by a mortise and tenon connection 38 which is surrounded with oil ema nating at the end of the tenon from the coaxially aligned holes 80 of the shafts. This oil travels along the surface of the shafts toward the respective rotors lthereby erforming the function of lubricatinfr the arings of the shafts in a manner similar to that ac- 4complished at the `outer ends of the shafts where ,the everresent oil in s aces 29 and 31 is bein forced continuously rom the ends of the sha ts and toward the respective rotors.

Grooves in the bearings are provided for the purpose of lubrication, the grooves bein arranged in a manner to permit a restricte flow of oil to the low pressure sides of the rotors, said grooves being in communication with a source of supply and lubrication being effected while the com ressor is operated.

The quantity of oil ed in this manner into the low pressure sections of each cylinder is dependent, inart, upon the design of the ooves'in the earings and, whatever their esi m'ght be, thorough lubrication of the sha ts within bearings 15, 16 and 17 is assured.

Holes 40a are drilled transverse to and throughvthe axes of the shafts close to the y serve to conduct oil from the-co-axially aligned holes 30, in the shafts tothe inner edges of the disks 41. The number of disks used is largely a matter of choice depending upon the increase in manufacturing tolerances desired. In the present disclosure, four disks are used with each rotor. The pressure on the oil within the shaft together with the effect of centrifugal force causes the voil which is delivered through holes 40a to travel toward the outer edges of the disks in the spaces therebetween, an between the disks and the rotor. The greater viscosity of the oil over that of the gas will reduce the leakage very materially.

The use of four disks divides a given total clearance between the parallel sides of a rotor and of c linder coverlates bv six b reason of the six spaces pro uced. `It is t erefore apparent. that if a total clearance of 0.002 of an inch be permitted the space immediately adjacent a side of a rote.' would be 0.00033 plus of an inch when four disks are used as compared to 0.001 of an inch when no disks are used. The use of more disks would increase in manufacturing tolerances of the rotor and cylinder cover-plates resulting from increased end clearance variation of manufacturing limits between the rotor and the cylinder cover-plates.

iso

The disks 41, particularly those adjacent the rotor, may be made of an anti-friction bearing metal. The disks are free to move axially but cannot rotate. They are prefer- Cil ably held from anytendency to rotation by pins or keys 41a fixed in the cover-plates and extending within holes in plates 41. The fit of the pins in the holes of the plates is loose lto permit the disks to space themselves axially to given even spaces. This even s acing caused by the even pressure of oil re uces a relatively large total clearance to a small effective operating clearance.

The oiler body 25 through which oil is conducted from conduit 24 to the low pressure side of the first stage compression cylinder 10 will now be described. Fitted so as to be capable of being displaced along its own axis is a threaded stem 42, the end of which may extend into a drilled hole or bore 43 into the oiler-body. This hole or bore communicates directly with passage 21. .The tapped por tion of the oiler body which en ages the threaded portion of the stem 42 a ove conduit 24 is of the usual standard which forms a snug fit about the stem. The tapped portion of the oiler-body which engages the threaded portion of the stem below conduit 24 is designed to form an helical channel about the -threads on the stem. This channel may be obtained by removing the apex of the thread in the lower portion of the' tapped hole by a drilling operation. This drilllng operation must leave the root of the outer thread unaltered so that the apex of the thread on the stem will be firmly engaged. The helical channel created about the lower portion of threaded stem 42 permits of a light feed of oil to the cylinder from conduit 24.

The quantity of oil fed into the cylinder through the channel is dependent upon the pressure in conduit24 and hence upon the load on the compressor. Ordinarily, the fiow might be by drops, but an increase in load will be accompanied by an increase Ain oil flow. The desirability of this self-regulation is apparent.

For insuring non-interference by foreignmatter of the flow of the quantity of oil fed to the cylinder through the oiler-body, an attendant. may withdraw the stem 42 to such an extent as to permit that threaded portion of the stem that normally serves to form a channel to be engaged by the unaltered portion of the tapped hole. The thread on the stem will be cleaned as a result of this operation without necessitating the shutting downof the-operation of the unit. A gland 44 and follower 45 is provided to assist in preventing a loss of pressure from the oler-body. All of 4the oil used in lubricating the vcompressors is carried away through the outlet ports with the refrigerant and is then separated therefrom andl strained preparatory to passing it again through the compressor.

The complete cycle of flow of the lubricant has been vdescribed and it will be understood that continuous lubrication of the compressor will be had as long as the compressor is operating, the difference in pressure upon the lubricant in the separator, and hence. in the oiler-body, and at the low pressure sides of the respective rotors being the propelling force by which complete lubrication is achieved.

I claim:

1. An oil feeding device comprising, in combination, a body having a tapped hole intersected by a passage, a rotatable stem having threads thereon snugly engaging the portion of the tapped hole disposed on one side of said passage and forming a channel `in the portion of the tapped hole disposed on the other side, of said passage, and means for said bodv having a snug fit portion and a( vchannel forming portion co-acting with said member, said channel forming portion forming a restricted How channel with said member, means to supply fluid yto and conduct Huid from said channel, and means to move the portion of the member forming the channel into engagement wtih the snug fit por-` tion to clean said channel.

3. An o1l feeding dev1ce comprislng. 1n

. combination, a body having a hole with a tapped portion, a threaded stem having a thread that cooperates with said tapped portion to create a channel therebetween, and means for supplying lubricant tok said body to force the same through said channel.

4. An oil feeding device comprising, in combination, a body having a hole with a tapped portion, a rotatable stem.threaded to cooperate with said tapped portion to create a channel therebetween, vand a conduit communicating with said hole to deliver oil to-said channel.

5. A lubricating device comprising a body having an internally threaded bore, an externally threaded stem of uniform size, a portion of the internal threads of the body extending to the root of the threads of the stem, and other of the threads of the body terminating in spaced relation to the root of the threads of the stem to provide a spiral lubricant channel around the stem and between the stem and bore.

(i. A lubricating device comprising a body having an internally threaded b'ore and an externally threaded stem of uniform size, a portion of the internal threads of the body extending to the root of the threads of the stem. and another portion of the body engaging the threads of the stem and providing therewith a spiral lubricant channel around the stem between the stem and bore. v

7. A lubricating device comprising a body having an internally threaded bore and an lexternally threaded stem of uniform size, a

portion of the internal threads of the body extcndin to the root of the' threads of the` stem, an another portion of the body engaging the threads of the stein and providing the stem between the stem and bore, said therewith a spiral lubricant channel around lubricant channel bein cleanable by retractsignature.

EDWARD T. WILLIAMS.

ing said stem to cause t e threads on the body -l I combination a body havin a lsaid bore, t

to interengage the threads on the stem.

8. A device of the class described comprisi ing a body having a bore with an intersecting passage, said ore being threaded at opposite sides of the passage the threads at one side being deeper than the threads at the vother side, and a stem having-threads of a uniform size for engaging the threads of the bore at opposite sides of said passage.

9. A device of the class described comprisl ing a body havinga longitudinally tapped bore, a stem having threads engaging the threads of the bore, the threads of a portion of the 'bore `being shallower than other of the threads to provide a lubricant channel, said lubricant c annel being cleanable b longitudinal movement of the stem in the d h 1Q. A lubricatin device comprising a avin low and cooperatin with the threads of the stein to provide a ubricant channel.

11." An oil feeding device com rising in ore with tapped portions, a threade stem having a thread t at is snugly engaged by one taped portion of the bore, the t reads of anot er ta ged portion of the bore forming a channel wit the threads of the stem, and means for supplying lubricant to said body to force the same throu h said channel.

12. An oil feeding device comprisingin combination a body having a bore with tapped pbrtions, a rotata le threaded stem adapted engaged by a ta. pcd portion of e threads of anot er tapped portion of said bore forming a channe with the threads of the stem, and a conduit communi- .to be snugly cating with said channel for delivery of oil thereto. y

13. A metering device comprising a body having a threaded bore, a threaded stem for cooperation with said bore, a portion of the threads of the bore cooperatin with threads' of. the stem to define a fluid c annel.

14. In 'a lubricating system, a resistance unit comprisin in combination, a threaded sleeve-like mem er, and a threaded resistance lug, the threads on the plug being different rom the threads on the sleeve-like member, both sets of threads cooperating to provide y a threade bore and a stem having threa s engaging the threads of the bod certain of the threads of the body being sh 

